Oil burner



June 19, 1928.

FLETCHER on, BURNER Filed Juiy 23,` 1926 3 Sheets-Sheet.hullllllllllllllrl June 19, 1928. 1,674,282

G. v. FLETCHER OIL BURNER Filed July 23, 192e -'sheets-sheet 2 June 19,1928.

. 1,674,282 G. V. FLETCHER OIL BURNER Filed July 23, 1926 5 Sheets-Sheet5 jig. .7

v Patented June 19, 1928.

, velocity.

l UNITEDKSTATES PATENT OFFICE.

GEQRGE lVAUGHN FLETCHER, OE MINNEAPOLIS, MINNESOTA.

' oIL BURNER.

' Application filed July 23,

' My invention relates to oil burners of the type wherein theatomizati'on bf oil isproin like characters indicate like partsthroughlv out the several views.

Referring to the drawings:.

Fig. 1 is a vertical section of the burner, showing the sameapplied `toa boiler or furnace, someparts being broken away', some parts beingshown in full, and some parts being sectioned on the line 1- 1 of Fig.2;

Fig. 2 -is av plan'view of the burner, .some

yparts sectioned von the line 2-2 of Fig. 1, and

some parts being broken away;

Fig. 3 is a side elevation of the burner, some parts being broken away;

Fig. 4 is an enlarged section taken on the line 4 4 of Fig. 1; and Fig.5 is a fragmentary section on the line 5-5 of Fig. 2.

In Fig. 1, the numeral 5 indicates a boileiner furnace having thecustomary ash pit 6, but provided with an annular supporting plate 7substituted for the grate and covered with an' insulating material 8,suchv as concrete. In the preferred mann r of installing the burner, theplate 7 and insulation 8'closely surround the upper portion of a largecup-like air trunk 9 into one "sidexof which air is blown through anair, intake pipe 10 'that is' connected to the discharge spout 11 of apower-driven fan or blower 12. The case of this blower 12 is mounted ona base 13, which is preferably a cast struct-ure provided outside of the'furnace with a laterally extended ground-engaging por/tion 14. Prefferably, therota'ry head ofthe blower 12 1s driven from a small electricmotor 15 supported on the base 13. They inner end portion of the base 13is adjustably supported by a screw-threaded leg 16 and the air trunk 9is adjustably supported on :tl' inner port-ion' of said base byscrew-threaded supporting legs 17, which adjustable features make 1t1926. serial No. 124,436.-

an easy matter to set the air'trunk 9 and Vthe bowl supported therebyand presently to be described in a true level position and at the properaltitude. l

The numeral 18 indicates a ycombustion bowl, preferably a cast structurehaving an outstanding rim ange 19'that rests on the upper edge of theair trunk 9, forming a close joint therewith. Also, the bowl,immediately adjacent its supporting flange 19,`

has a Short cylindrical portion 20 that telescopes into the air trunk9'Y and keeps the lower portion of the. bowl concentrica-lly spaced fromtheI walls thereof, so that the air inthe trunkran sweep completelyaround the bowl below said cylindrical portion 20.

, At a plurality of points, as shown at four points circumferentiallyspaced, the bowl 18 isforinedpvith air intake ports 21'and 21a. The port21a has considerable length/cir cumferentially of the bowl and willdirect thel air delivered,therethrough against the peripheral wall ofthe bowl, vcausing the same to directly take up a whirling motionagainst the inner surface of the bowl. The oil or fluid fuel will bedelivered into this port 21 and', hence, the bottom of said port isinclined toward the interior of the bowl so thatl surplus oil will notrun out of the bowl. fThe ports .21, of which, 'as shown, there arethree, openfsub'stantially taugen tially into the bowl, but they are cutor formed so that lthey do' not have thevsame tendency to cause the airto hug the peripheral "wall of the bowl, but lrather tend lto direct theair spirally inward and toward the axis of the bowl. The-importantaction produced by these cross currents will be further considered inthe descriptiolLof the. operation. 4 A j -v The numeral 22 indicates a.drain pipe or tube applied to theibottom and depending from the centerof the bowl. The upper portion of the bowl is formed as a separateannular ele1nent'23tl1at is contracted. This portion 23 vwill besubjected to they most intense heat and, it being separately formed,may7 be made of carborundum or other material that is more highlyrefractory thanf` the cast body of the bowl.- Even when the upper rimportion 23 of the bowl is ofcast iron or steeLit should be formedseparately from the bowl so that it may be readily to the body of thebowl, it'fis` shown as rabbeted at its lower edge and made to looselyfit a correspondingly rabbeted' portion of the bowl, as at 24.

In this preferred arrangement, the oill or -fluid fuel is delivered tothe air intake port 2l through a pipe 25 that is extended 'l through theside "of the air trunk 9 and is tapped through the side of the bowl sothat itidelivers .the oil at the very top of said any suitable'source,such as an elevated tank or `pump, so far as this invention isconcerned. Y

In connection w1th an oil burner if this character, a pilot. light,suchI jas a small gas yilame maintained within the bowl for effect- `inginitial combustion of the 'oil vapor, is

desirable; and this pilot is preferably arranged as'follows: A small gaspipe 27 is extended through and spaced from the walls of .the drain pipe22 and at its lower end is screwed into acoupling 28 shown as secured'to 'and vdepending from`the bottom of the air trunk 9 by threadedenga-gement at `29. This coupling 28 has two compartments 30 and 31. Thelower end of the gas pipe 27 leads upward from the compartment 30 andthe lower endof the drain pipe 22`extends' .downward into the open-upper portion of the chamber 31 but'is spaced from the 'walls of thelatter so. that said chamber 31 affords a drain from the bottom of theair trunk.

Elbows 32 and 33 are screwed into the coupling 28 and communicate,respectively, with the chambers 30 and 31. 'A gas supply pipe 34 leadsto the elbow 32 and a drain pipe 35 leads from the elbow 33 to asuitable point of discharge.l A pilot head 36 is applied to the upperendof the gas pipe 27, as shown, vby threaded engagement, and isprovided with a plurality ofl downwardly sloping gas discharge passages37 that directs the plurality of pilot flames onto or immediately abovethe bottom of the bowl.

Summary of operation.

When the blower is in action, air pressure will be produced in the airtrunk 9 and air from `said trunk will be discharged into the bowlthrough the several tangential air ports 21-21. thus delivered into thebowl will set up a. violent whirling orv cyclonic action within the bowland the air inthe air trunk sur- The several streams of airy roundingthebowl will also be caused to' whirl .to some extent thereby insuring aneven supply of air through the several air ports.

The oil delivered into the bowl from the fuel pipe 25 will be primarilytaken up by the air introduced into the bowl through the port 21a. Theair-introduced into the bowl through the port 21a will be directedagainst the -wall ofthe bowl and, under the action of centrifugal force,will tend to hug the wall of the bowl and revolve therein with an upwardspiral trend. The'air delivered into the bowl'through the several ports21 will also be given a spiral rotary movement within the bowl, but theair currents thus introduced will have a trend toward the axis'of thebowl, so that they will cut through the whirling oil-laden air blastintroduced through the port 21a. .These cross currents or currentshaving the greater inward trend break up or tend to break up the primaryspiral oil-laden current, thereby producing a thorough intermingling ofthe several cur rents and a turbulence of air currents'that insures themost complete atomization of theH oilv and most thorough commingling ofthe oil and air. Moreover, the inward trend of the disrupted crosscurrents introduced through the ports' 21 very greatly improves theaction of the burner, not only generally 'but particularly at the centerof the bowl, where there will be a tendency to more or less incompletecombustion, resulting in some ultimate accumulation of carbon at thecenter'of the bowl, whereas, with the arrangement described, suchincomplete combustion and accumulation of carbon is eliminated.

Of course, centrifugal force will keep a greater part of the whirlingoil-vapor-laden air whirling against Vor close to the wall of vthe bowlso that the ultimate yupward discharge thereof from the bowl will beretarded by the contraction ofthe rim` portion of the bowllong enough tocause a most complete vaporization of the oil. The combusf tion wll bestarted within the bowl, but the flame and the complete combustion willtake place above and outside of the bowl. Cen* trifugal force, acting onthe whirling vaporladen air, will cause an expansion of the flame into acup-shaped or saucer-shaped flame immediately upon its discharge or`release from the rim of the bowl, with the re sult that the flameproduced will be properly' spread for the most complete combustion andmost effective -heat production.

It will be noted that-the` pilot throws a. plurality of flames ,radiallyoutward from the center` of the bowl and that the commingled air and oilare caused to whirl around the pilot in such manner that quick ignitionis insured and there is a minimum of tendency to blow out the pilotflames.

llO

I Vhen the burner is in action, the air laden with oil or vapor in theproper mixture for combustion will, as already indicated, be dischargedfrom the top of the bowl in an annular out-spreading blast. Tests haveshown that, at such time, there will-be a flow of hot air from thecombustion chamber' axially downward into the bowl. This downwardlyflowing stream of hot air, upon entering the bowl, is also caused torotate and, as it spreads, will commingle with or act upon the vaporizedoil and further assisty in the final and more complete atomizationthereof, so that the oil vapors will reach the flashing pointas they aredischarged from the bowl.

The eiiicieney of this comparatively simple burner has been thoroughlydemonstrated in practice and the statements herein made are based onactual experience and tests in the use .of the burner. A

IVhatI claim is:

l. In an oil burner, a combustion bowl having a. plurality ot'vperipheral circum-l ferentially spaced air intake port-s, means forintroducing air into said bowl through said ports, thereby setting up awhirling motion of the air within the bowl, and oil delivery meansopening directly into at least one of said ports that is4 locatedbetween certain other of the air ports, into which latter oil is notdelivered. i

2. The structure defined in claim l in which the air port into which oilis delivered has a bottoni that inclines toward the interior of the.bowl. Y

3. An oil burner comprising a cup-like air trunk, a blower connected toSaid air trunk, a. bowl detachably mounted on the rim of said air trunkand depending thereintobuti, spaced from the sides and bottom thereof,

u' said bowl having peripheral air intake means for delivering air fromsald trunk vinto said bowl and setting up a. whirling motion of the airin the bowl. and a separately formed rim portion 'detachably mounted onsaid bowl.

4. The `l`structure defined in claim 3 in which said detachable rimportion is contracted toward its upper edge.

5. In an oil burner. the combination with a bowl having a plurality'ofperipheral circumfercntially spaced air intake ports. means forintroducing air into` the bowl through said ports. thereby setting up awhirling motion of the air within thebowl,

and an oil delivery port opening directly said air intake ports.

6. The structure defined in claim 5 in which said bowl has a wallportion below the oil intake port and over which the oil will run fromsaid port toward the bottom of the bowl while it is being acted upon bythe whirling air. i

T. In an oil burner an air trunk, means for deliveringl'air into saidtrunk, a bowl set into said trunk and having peripheral air intake portsfor delivering air from said trunk into said bowl and causing the sameto whirl within the bowlfmeans for delivering oil into said bowl,whereby it will be taken up and vaporized by the air whirling p into theupperportion of at least one of'v within the bowl` a two-compartmentcoupling applied to the bottom of said air trunk and formed with gas andoil` chambers, the

a. gas supply pipe leading to said gas charnber, a. gas pipe extendedupward from said gas chamber and provided with a delivery head locatedWithin the bowl, a ydrain pipe surrounding said gas pipe and extendedfrom the bottom of lthe bowl into the oil latter opening into the bottomof said trunk,

through the whirling air current first noted and with a greaterv trendtoward the axis of the bowl, and means for introducing oil into the bowlwhere 'it will be taken up and vaporized by the whirling air wit-hin thebowl.

9L In an oil burner, a combustion ybowl having afplurality of peripheralair intake ports, at least one thereof being arranged to introduce theair substantially tangentially and at least one of said ports being ar'ranged to introduce V air into the bowl through the whirling air currentfirst noted and with a greater trend toward the axis of the bowl, andmeans for introducing oil into said bowl at the first noted air intakeport.

In testimony whereof I aliix my signature;

GEORGE VAUGHN FLETCHER.

